化工学报 ›› 2018, Vol. 69 ›› Issue (9): 3851-3858.DOI: 10.11949/j.issn.0438-1157.20180253

• 流体力学与传递现象 • 上一篇    下一篇

高宽比对矩形通道内蒸汽冷凝传热特性及流型影响的研究

严彦1, 董继先2   

  1. 1. 西安工程大学机电学院, 陕西 西安 710048;
    2. 陕西科技大学机电学院, 陕西 西安 710021
  • 收稿日期:2018-03-12 修回日期:2018-05-21 出版日期:2018-09-05 发布日期:2018-09-05
  • 通讯作者: 严彦
  • 基金资助:

    国家自然科学基金项目(51375286)。

Condensation heat transfer characteristic and flow pattern of steam in rectangular tube with different aspect ratio

YAN Yan1, DONG Jixian2   

  1. 1. College of Mechanical and Electrical Engineering, Xi'an Polytechnic University, Xi'an 710048, Shaanxi, China;
    2. College of Mechanical and Electrical Engineering, Shaanxi University of Science & Technology, Xi'an 710021, Shaanxi, China
  • Received:2018-03-12 Revised:2018-05-21 Online:2018-09-05 Published:2018-09-05
  • Supported by:

    supported by the National Natural Science Foundation of China (51375286).

摘要:

通过可视化流型观测及实验测量,研究了单边换热矩形小通道的高宽比对两相流型、平均冷凝传热系数及两相流动阻力的影响,采用高速摄像机拍摄了环状流、环波状流、波状流、弹状流、塞状流及泡状流6种典型流型。研究表明,高宽比为1:2及1:3的通道内出现流型种类较为全面,而在高宽比为1:5通道内基本无弹状流、塞状流及泡状流。1:5通道内环状流所占区域较1:2及1:3通道大,随入口蒸汽质量流速的增加,差值逐步减小。随着通道高宽比的减小,平均冷凝传热系数逐渐增大;不同高宽比通道中平均冷凝传热系数间的差值随入口蒸汽质量流速的增加而减小;蒸汽质量流速足够高时,高宽比对传热系数基本无影响。通道内两相流压降随通道高宽比的减小而增大;随着入口蒸汽质量流速的增加,不同比例通道内的两相流动压降差距逐渐增大。

关键词: 矩形通道, 高宽比, 流型, 凝结, 传热

Abstract:

An investigation on single side condensation of vapor inside a horizontal rectangular tube was performed. The influences of tube aspect ratio on flow pattern, heat transfer coefficient and pressure drop were analyzed. Annular flow, annular-wave flow, wave flow, slug flow, plug flow and bubbly flow are observed. Flow pattern appearing in larger aspect ratio tube was more comprehensive than in small one. The area occupied by the annular flow increased with the decrease of the aspect ratio, but the difference gradually decreases with the increase of mass flow rates. Heat transfer coefficient and pressure drop increased with aspect ratio decreased while mass flow rate was small. With the mass flow rate increased, the difference for heat transfer coefficient decreased while for pressure drop increased.

Key words: rectangular tube, aspect ratio, flow pattern, condensation, heat transfer

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